Function description
APCIe-040
The digital inputs acquire external signal statuses. The input information is loaded as a numeric value
in a memory cell of the system via the driver function. This numeric value represents the status of the
input signals.
The inputs correspond to the 24 V industry standard (IEC1131-2):
•
Logic “1” corresponds to an input voltage > 19 V.
•
Logic “0” corresponds to an input voltage < 14 V.
The current demand for each input is 5-8 mA at nominal voltage (see Chapter 7.4.1). The maximum
input voltage is 30 V.
i
IMPORTANT!
The mains supply for the external power supply of the board must
deliver at least the power that is required for your application.
The input signals are filtered by TVS diodes, RC filters and opto-couplers. In this way, the effect of
inductive and capacitive noise is reduced.
4.3
Digital outputs (relays)
The switching principle of the relays is explained in Fig. 3-7. Each output can switch a maximum current
of 2 A.
The warning relay and the reset relay functions are software-selectable. For the digital outputs,
positive logic is used:
•
Logic “1“ = Set output (connection: change-over contact with closing contact)
•
Logic “0“ = Reset output (connection: change-over contact with opening contact)
4.3.1
Watchdog 0
When watchdog 0 has run down, warning relay 0 or the reset relay is switched (see Fig. 4-2). The reset
relay can be switched in two different ways:
•
Mode 0:
The reset relay is first reset and after 2 s set again.
•
Mode 1:
The reset relay is first set and after 2 s reset again.
4.3.2
Watchdogs 1-6
When watchdogs 1-6 have run down, warning relays 1-6 are switched. The latter can be reset by a
computer reset or a reinitialisation of each of watchdogs 1-6.
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